Drilling and deflecting tool



May 5, 1959 D. B. HERING DRILLING AND DEFLECTING Toor.

5 Sheets-Sheet 1 Filed Sept. 24, 1956 INVENTOR. 0A /v/fL B. HER/:v6

May 5, 1959 maur-:RING 2,885,182

` DRILLING AND DEFLECTING TooL Filed sept. 24, 1956 sheets-sheet 2 v HG. 6

IN V EN TOR. DA /v/H HE@ m16 May 5, 1959 D. B. HERING DRILLING AND DEFLECTING TooL Filed Sept. 24, 1956 5 Sheets-Sheet 4 INVENTOR. 0A /V/ fz H5@ N6 F/G., i0

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May 5, 1959 D. B. HERING DRILLING AND DEFLECTING Toor.

5 Sheets-Sheet 5 Filed Sept. 24,- 1956 i`-v........llv

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mi/3-v n 223 iii Fla. I6 m INVENTOR. DAN/,a B. #5R/N6 n ABY l Afrogmrs' DRILLING AND DEFLEC'HNG T001.

`Baniel B. Hering, Lakewood, Calif., assignor'to Driltrol, ,Long Beach, Calif.

Application September 24, 1956Seral No. 611,570

19 Claims. (Cl. 255-1.6)

rl`his invention relates to :a new and improved drilling and dellecting tool. Thisy application is a continuation in-part of my co-pending patent applicationsy Serial No. 486,329, filed February 7, 1955, now abandoned, and Serial No. 514,646, led lune l0, 1955, now abandoned. For various mechanical or geological reasons itis sometimes desirable .that the course of an existing bore hole for an oil or gas well or similar hole be diverted Vor deected from its existing direction, so that a new section of the hole assumes an `angle with respect to the preexisting section. The present invention relates to a tool which may be used to accomplish this diversion or deliection.

One distinction between-the present invention and other tools heretofore used for dellectingV bore holes is emphasized by consideration that in previously used tools it is necessary first to drill a hole 4with a conventional drilling tool Vto the desired depth, then raise that tool to the surface, insert a tool which accomplishes deflection of the hole, perform :the vdeflecting operation, then remove the deflecting tool from the hole, and then reinsert the conventional drilling tool and continue drilling ,in the deected direction. The tool which is the subject of lthe present invention may be used to drill to the desired depth, then deflect the hole, and continuedrilling in the deected direction, all without removing the tool or any part of the tool, from the hole. 'This is of considerable advantage in that removal and reinsertion `of ak drilling tool and the -drill pipe string is extremely expensive, both from the standpoint of wear and tear on the machinery, fuel consumption and rig and crew times. Accordingly, the present invention eliminates the time and expense involved in conventional operations.

Another `feature of the invention is the fact that means is provided' to orient the tool to kdeflect in any desired direction. Furthermore, the tool may be used to make several successive deflections without removing the tool from the hole at different depths. The succeeding deections may be made in a rdesired direction ditferent from the preceding deflection.

The present invention comprises a tool which may be lowered into the bore hole and employed to drill the hole in a manner quite similar to conventional drilling practices until s uch time as deflection of the hole is desired. Thereupon the present tool may be used to accomplish deection of a new section of the bore hole at an angle with respect to the pre-existing section. Thereafter the new section ,of the hole may continue to be drilled by means of the present tool in a manner substantially similar to conventional drilling practices. One of the features and advantages of the present invention is'y the fact that the tool may be used alternately for conventional drilling and deflection drilling without removing the tool from the hole for a number of alternations until the drilling of the hole is completed.

Another featureof the invention is vthe fact that it em.- ploys a guide used to deflect the direction, of the hole, which guidi? may be .retracted to an Ainoperative position e2 whereupon the tool may be'used for drilling in 'a conventional mannerandthe guide may be vprojected and retracted as desired, without Ithe necessity of returning the tool to the surface.

One of the principal features and advantages of the invention is the provision of latch means operable to latch the guide in retracted position and further latch means to latch the guide in projected position, both latch means being preferably operable both-for latching and unlatching without raising the tool to the surface.

Another feature of the invention iis the fact that the means which holds the guide in projected position comprises a latch which may be repeatedly latched and unlatched, thereby differing `from `other tools of `the same general type which `employ s'hearpins and similar instrumentalities which may be accidentally broken and hence prevent yproper'orientationof the tool. The tool which is the subject of the present invention may, accordingly, be positively oriented lin proper direction and the guide locked against rotation whiledeflecting.

Another principal feature of the .present Yinvention isthe elimination of a whipstock, `which is the common means of deflecting .bore holes at the present time. Further, the present invention eliminates the necessity of drilling the deflectedhole, termed the rathole, at a reduced diameter as compared with the .diameter of the pre-existing hole, which is a feature of whipstock drilling at ythe present time.

The present invention materially reduces the amount of time required to deflect a'bore hole, as compared with prior tools intended to accomplish the same purpose. The reduction in the time required is Aaccomplished in large part by eliminating the necessity vof returning the working tool to thesu-rface by `withdrawing the drill pipe and then lowering a new tool and drill pipe vinto the hole. The elimination of the replacement of the working tool results in a considerable decrease in drilling costs, particularly when the drilling is' being `conducted far below the surface.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

Fig. 1` is a side elevation partly 'broken away in section showing one form of the tool at the completion of drilling of the pre-existing: hole, with the guide re` tracted;

Fig. 2 is a view similar to Fig. 1 showing the drill retracted and the guide extended to commence drilling of the deflected hole;

Fig. 3 is a View similar to Fig. 1 showing partial completion of deflection of the borehole;

Fig. 4 is a transversesectional View taken substantially along line 4 4 of Fig. 2;

Fig. 4A is a transverse sectional View taken substan tially along line 4A-4A of'Fig. l;

Fig. 4B is an enlarged fragmentary longitudinal sectional view of the upper latch;

Fig. 5 is an enlarged fragmentary sectionalview of a modified upper latch;

Fig. 6 is an enlarged fragmentary longitudinal sectional view of a modified lower latch;

Figs. 7, 7A, 8 and SAIare enlarged fragmentary lon-` gitudinal Vsectionalviews of still other modified latches;

Fig. 9 .is afragmentarylongitudinalsectional view of a spring-hiasedknuckle joint used in stilla further modiication of the invention;

Figs. 10 and,l2 are longitudinalsectonal views of additional modifcations of the invention;

Fig. 1l is a view taken substam tially along line 11--11 of Fig. 19;

Fig. 13 is a side elevation, partly broken away in section, of a modified tool shown at completion of drilling of the pre-existing hole, with the guide retracted;

Fig. 14 is a longitudinal vertical `sectional. view showing the drill retracted and guide extended to commence drilling of the deilected hole;

Fig. l is a view; similar to Fig. 14 showing partial completion of detlection of the bore hole;

F-ig. 16 is a view similar to Fig. 14 showing completion of deilection with the guide retracted;

Fig. 17 is a transverse sectional view taken substantially along line 17-.17 of Fig. 14;

Fig. lzis a longitudinal; vertical sectional view `oil? a modified lool;

t Fig. i9 is a fragmentary vertical sectionalview of the upper end` of the `tool `showing a latch `in latched position;

Fig. 20 is a view similarlto Fig. 19 showing `the latch being unlatched.

As shown in` Figs. l-4B of the accompanying drawings. a pre-existing` bore hole 21 extends vertically and a new bore hole 22 is tobe drilled at an angle to the pre-existing hole. It will` be understood that it is not necessary that the preexisting hole2l be vertical and, further, that the angle which the new hole 22 assumes to preexisting hole 21 is subject to considerable variation.- In order to accomplish dellecton of thenew hole` a tool isemployed, as hereinafter described in greater detail, at; the lower end of a string of drill pipe 23. If desired, `the tool may be usedto drilloriginal hole 21 as well as deliected hole 22. The tool may be alternatelyk `usetl to drill a section ofthe hole along a pre-existing direction and `then dellect along anew section,. without the necessity of `withdrawing the :tool to the surface.

The tool comprises a barrel 26 having at itslower end an apertured drilling bit 27herein termed the core bit by reason ,ofi its similarity to bits employed to sample formations `by coring and a guide 28projectable and retractablefthrough the aperture 29 in bit 27. I'he barrel 26 has an extended cylinder` portion 31 above core bit 27. Above cylinder portion 3l` the barrel is formed with a reduced `diameter section 32, there being a top shoulder 33 atthejuncture of the cylinder portion and the reduced diameter portion which limits upward movement l of guide 28'inside barrel`26. Above shoulder-33 is an upperlatch cavity 34 hereinafter described in greater` detail. Adjacent the `lower `end of cylinder portion 31 is a deected cylindrical section 36 of substantially the same diameter as cylinder portion 31, said deflected cylindrical portion veering outwardly relative to the central axis of the barrel. Below deflected cylindrical section 36 is core bit 27, the construction of whichis subject to considerable variation, as will be understood by those skilled in the drilling arts.

Bit 27 is so constructed as to drill a ho1e2l of substantially greater diameter than the outside `diameter of barrel 26. As has been heretofore set forth, bit 27 is formed with central aperture 29. Above aperture 29 intermediate said aperture and the lower end of deflected cylindrical section 36, the internal diameterV is reduced to `a bottom shoulder 37. A lower latch cavity `311,. hereinafter described in greater detail, `is formed near shoulder 137. h

Guide `28 comprises an elongated stern 41 having a guide bit 42at its lower end. A piston 43 isformed on the ripper end of the guide stem, said piston having an outside diameter such as to slide longitudinally in both cylinder 3l and detlected cylindrical section 36. Above piston 43 is a restricted diameter head 44 formed with a recess46in which `a latch 47 is mounted by means of pivot pin v48, spring 49"`biasing latch 47 outwardly. Latch 47 and upper latch cavity 34 are so related that when in latched position the working enti 51 'rs of latch 47 is held retracted, with the point of guide bit 42 drawn within or near to.aperture 29 of core bit 27. However, the point of guide bit 42 is suiciently close to the lower edge of core bit 27` that when the tool is turned in a bore hole, guide 28 tends to remain stationary and this tendency is used automatically to unlatch the guide when the tool is turned in the reverse of the direction for normal drilling. Working end 51 of latch 47 is formed with a vertical outwardly extending surface 52 on one surface and a rounded, beveled shoulder 53. The lower edge 54 of the working `end is substantially horizontal. Bottom wall 56 of upper latch cavity 34 is slightly helical and at its uppermost point terminates in vertical wall 57 against which vertical surface 52 engages so that guide 28 and barrel 26 rotate in one direction together. Outer wall 58 of cavity 34 and also the upper wall 59 thereof are eccentric, having their maximum outward projection against vertical wall 57 and diminishing as the helical bottom wall 56 lowers. It will thus be seen that when the tool is turned in a reverse direction, guide 28 remains stationary, latch 47 is retracted until guide 28 is unlatched, thereby` permitting the guide to project through aperture 29 in core bit 27 when the toolis raised from the bottom of the bore hole.

Below piston 43 a seat 61 is formed on stem 41, which seat engages the corresponding aperture 29 in core bit 27. A recess is formed in scat 61 and bottom latch 77 which functions to secure guide 28 in projected position, is pivotally mounted in said recess by means of pivot pin 78, latch 77 being biased outwardly by means of spring (not shown) in said recess. t The upper edge of latch is slanted and `the `corresponding upper wall 103 of latch cavity 38 is likewise slanted. Hence when extreme downward force is applied to barrel 26, latch` 77 is retracted, permitting barrel 26 to be lowered while guide 28 remains stationary.

In use, as shown in Fig. 1,. centrally apertured core bit 27 is employed to drill pre-existing bore hole 21 in substantially conventional manner with guide 28 retracted within `the barrel :and latched in position by upper latch 47 seating in latch cavity 34. Normal turning of drill pipe 23 causes surface 52 and wall 57 to engage and hence guide 28 turns with barrel 26. Assuming that it is desired to drill a deflected hole 22 after pre-existing hole 2l has reachedthe depth indicated in Fig. l, the operator turns drill stem 23 in a direction counter to normal drilling direction, which causes upper latch 47 to unseat from latch cavity 34 and then raises the tool from the bottom. The force of gravity and fluid pressure applied above piston 43 cause guide 28 to move to its fully extended position shown in Fig. 2, whereupon lower latch 63 latches the guide in projected position. By reason of the odset or deflected cylindrical section 36, guide 28 locks at an obtuse angle with respect to barrel 26. By rotating drill pipe 23 the tool is turned so that guide 28 projects in the desired direction for new hole 22. The means whereby the guide is accurately located in proper direction forms no part of Wthe instant invention and hence is not herein described, being well understood in this art.

In Fig. 2 the tool is shown in position at commencement of the deflected drillingoperation with the guide bit 42 forced firmly into the formation at the bottom of pre-existing hole 21 and osetto one side from the central axis of the pre-existing hole. Lower latch 77 is then unlatched by means heretofore explained and thereupon drill pipe 23 and barrel 26 are lowered and turned, causing core bit 27 to be deflected in the direction of the new bore hole. During dellected drilling, as shown in Fig. 3, fluid pressureis applied above piston 43, thereby holding guide 28 in position. The bending of barrel 26 to accommodate deflection is exaggerated in Fig. 3. The deflected drilling operation is continued until guide 28 is ,reseated inside barrel 26 and latched MMI" will www l.. t

therein, ,whereupon the" tool .continues todrill new hole: 22 in the proper direction,

The uid pressure employed against-piston 43 may be drilling compound. Itis desirable that meansforcir culation of drilling compound to guide bit 42 be provided while the tool is in drilling position, but not necessarily'when the tool is in deflecting position. Accordingly, as shown` in Figs. l-3, inclusive, circulationl ports 71fare formed in core bit 27 extending from the deflected cylindrical section 36 to adjacent the bottom of the tool. Similarly, circulation ports 72 are formed in guide bit 42. The location of the entranceof circulation ports 72 is such that when guide 28 is retracted, as shown in Fig. l, the duid circulates both through ports 72 in the guide bit and `core bit 71. However, as soon as guide 28 Vis projected, iiow throughguide bit circulation ports72 is cut off. Piston 43 is formed with longitudinal circulation ports 73 of restricted size, causing a lossof pressure due to increased friction and the loss of pressure results in a pressure differential above and below piston 43. This pressure differential creates downward thrust on the guide stem, which tends to hold said guide stern in position while deiiecting.

A- modified latch 77a which holds the guide 28a in retracted position is shown in Fig. 5, wherein the pivot pin 7S on which latch 77a is mounted is located below the working portion 79-of the latchand the latch cavity 34a in the restricted diameter upper portion 32a of barrel 23a is constructed essentially similarly to the corresponding parts shown in Figs. 1-3.

In Fig. 6` the latch 81 which. holds the guide 2812 in retracted positionin barrel 321: is shown further modified, withthe pivot pin 82v for the latch located'. atthe4 top andspring 49b biasing latch 81outwardly.

Thelatches of Figs; 5.and 6 maybe located either at :the upperor lower endof thestems 28a or;28b, or at an intermediate position.

In Fig. 7 is shownafurther modification for releasing the latch 86 which .holdsthe guide 28e-.in deliecting position. In this modification, latch 86 is pivoted by means of pin 87fand biasedoutwardly by tension springSS. The. barrel 32e of` latch cavity 89 isprovided` with-A a. central cylinderv91 in which reciprocates fa double-ended piston 92. Spring 93 -in the bottom of cylinder 91 biases the double-ended piston upwardly. The upper. end 94 of piston 92 lits `within the cylinder 91-andwhen excessive uidfpressureis applied from the surfacepistonv 92de forceddown. On the downward stroke, the loweriend 96 of piston 92 `engages the inner end `of latch86, causingfvthe latch to retract. Upon release of fluidpressure at the surface, springI 93 returnspiston 92'to upper` pof sition, whereupon latch spring 88 biases latch 86to extended position. Port 97 in cylinder 91 permits restricted circulation of fluid. It should be noted that, .by

changing .the shape of .the latch and position of .its.pivot,.

anumber of variations may be obtained, any of whichv willsatisfythe need ofy a latch, .lockableor unlocklable by use of fluid pressure.

In Fig. 7A is shown a latch similarto thatof Fig...7 modified in that it is employed as `an upper latch. Accordingly-latch 86a and cavity.89a are..shaped for such function andthe other parts are substantially the same and are illustrated with the same reference numerals. Spring 88 is of i sufficient strength to support theweight of guide 28C when `in retracted position.

In the event that itis desired .to relatch guide 28 if it should accidentally dropout of barrel.26, a Spearhead Llflfmay` be formed .above head 44. A- conventional overshot (not shown.) islowered intozdrill. pipe 22 on. a wire line land .is used to engage ySpearhead 101to lift guide 28.

After raising` guide 28 the toolis .lowered'tothevbottom of .the hole Yand rotated in the directionused for drilling until latch 47 islatched` in cavity 34. Then. theover-` shot is released and removed-and .drilling may -be started..y

Referencek is.now made toFigs.- 1 andf4 wherein/there:- is provideda `latch 77 mountedbymeans ofpivot pinl 78 in..an appropriaterecess in stem 41-and biased outto Fig. 1 thatthe internal diameter of core bit 27 aboven latch cavity38^is greater than the corresponding diameter below the latch cavity. The force required to f lower'orproject guide assembly 28"is substantially less than the force required to lower core bit 27 over guidev Further, the partsmay be constructed so that guide 28 must be pumped into extended position by application of fluid pressureon piston 43, whereas it is desirable .that considerable force be required inl order to lower core bit 27 over guide 28.

Referringnow to Figs; 8 and 8A, there is provided a latch260'which may be employed for latching the guide 28d both in extended anrilretracted positions. is pivoted by means of pin 261a ina recess 262:2 in such manner that it canv be moved to an extended position substantially transverse to the axis of rotation of the tool and may be retracted by pivoting upwardly. Spring 26421 biases latch 264) outwardly. A pair of latch cavities 266 and 267 are located in the barrel 268. Lower cavity 266 is located so that when guide 28d is in'fully projected position,.latch 260 is directly opposite the latch cavity.

266; Irregularly shaped upper latch cavity 267 formed in the wall of barrel 268 is located in such position that it is. directly opposite latch 260 when the guide is in fully retractedposition.' The lower edge 2710i 'latch 260i is .slanted and the lower edge 272 of cavity 267 is-likewiseslanted to hold guidel 28d in retracted posi` tion; The upper `edge 276 of latch 260 is bevelled and the upper wall 277 of cavity 267 is likewise bevelled. Upward pressure` on guide 28d when sufficient to overcome the force of spring 264 unlatches latch 260. Similarly the upper edge 278 of cavity 266 is slanted to unlatch the latch when upward pressure is applied to guide 28d and this effect is augmented by ball 279 inserted inedge' 278.

in the modification shown in Figs. 13-17 the tool is installed on the lower end of a drill stem 220 and' lowered into the bottom of pre-existing bore hole 221. The lowermost portion of the tool is a conventional core bit 222, or similar device, the details ofthe construction of which form no part of this invention. Such a core bit 222'isformed with a central downwardly tapering bore 223 through which, in conventional usage, the core of `the holeformation is received. It will be understood .that'the shape of bore 223 is subject to considerable modification in common commercial practice. Immediately above core bit 222 is a barrel 224 of lesser outsidel diameterv than bit 22). Barrel 224 and core bit 222 are'fsecured together by athreaded connection 226. The barrel 224 is hollow and elongated bore 227 thereof is formed with an offset, outwardly slanted portion 228 adjacent its. lower extremity of substantially the saune diameter as bore 227. It will be understood that kthe parts illustrated are round, but often other cross-sectional shapes may be employed. The offset portion 228 slants outwardly in one-direction toward the wall of barrel 224 so that hole 22S is offset from the center of `barrel 224. immediately above the lower-end of offset hole portion 228 is ashoulder 229 which is located, preferably, on the side tof yhole 228 toward which the offset portion is offset. Insteadofanabiupt shoulder 229, a tape-red reduction in hole size may be substituted.

Retraotablefwithin bore 227 of barrel 24'isa .guid 231 formed of a somewhat flexible rod or tube and Latch 260 :teenies comprises a piston reciprocal-lle in a cylinder comprising bore sections1227 and 228. Latch 256 which in `IatIchcmrty 252 holds guide231 in `retracted position.

ln usephole 221 is dug by a conventional bit `or by core bit 222to the required depth, latch 256 maintain- 231 retractedtseeFig. 13). It a conventional bit has been employed `in `drillinghole 221, it is withwn anda core bit 222 and barrel224 installed.` In

dra

anyevenrt. the core bit is raised from thelbottom of hole 221 a `distance substantially equal to the length of guide `231fand` `barrel `224 accurately located with shoulder; 229 offset in the proper direction so that guide 231I `will 1he projected parallel `tothe direction of the` slant boleto he drilled (Fig.l4). t

It will; be `understood that in conventional drilling practice drillingmud is pumpedthrough the hollow stem into the bottom of the drill hole. This feature of conventional `drilling apparatusis used in the present invention. The mud or some other suitable lluid is pumped through hollow drill stem 220 into hole 227 in barrel 224. The pressure of the uid on guide head233a forces `the-guide head downwardly untilgude 231 projects through bore 223. Thereupon additional weight is applied and guide bit 232 lodges securely inthe bottom of hole 221 (Fig. 14). With guide `bit 232 lodged in the position-shown in Fig. 14, drill stem 22|)l is lowered. Accordingly, llexible drill guide 231 is bentslightly,

allowing core bit 222 to go down hole 221.far enough so guide head 233a is removed froml oset: portion 228 in bore 227; (see Fig.` l5). VThe drill is then rotated. By reason of` the fact that guide 231 is otlsehzpressure is exerted againstthe side of hole 221 and slantldrilling commences. Drill stem 220` is lowered and turned slowly, resulting indivergent drilling of slant hole 236 as bit 222 follows guide 231.` During the operatiomlluid pressure is maintained against head 233a in ordertthat guidebit 232 be maintained in position.` When normal drilling of slant hole 236 maybe com-1 menced, the hole guide is retracted in barrel 224 (Fig. 16).'

In normal usage, as shown in Fig.116, sutlcient drilling huid llows between `head 233a and bore 227 for normal 8 Head 233 is formed with a peculiarly shaped recess 257 extending downwardly from the top of the head. An abutment 258 is formed in head 233 which limits upward movement of latch 256. Latch 256 is mounted in recess 257 on horizontal pivot pin 259 and moves from latched position in full lines` in Fig. 20 to the unlatched position shown in dotted `lines in Fig. 20. Extension 261 of recess 257 provides clearance for latch 256 when the latter is in unlatched position. Spring 262 at the bottom of 4hole 257 biases the inner end or head 263 of latch 256 upwardly and thusl biases latch 256 into unlatched position. Head 263 is substantially circular, as shown in Fig. l1, and tits tightly against a portion 264 of the hole,\which functions as a cylinder, whereas head 263 functions as a piston. As llud pressure is applied through drill stem 220, barrel 224 is rotated until its position relative toglatch 256 is that shown in solid lines in Fig. 20. When barrel 224 is* then raised, a combination of gravity and pump pressure, or either alone, hold head 263 and latch 256 in the position as shown in Fig. 19. The force of spring 262 is such that it will raise head 263, thus unlatching latch 256, when ud pressure is released, and guide bit 232 put on bottom to force head 233 to `uppermost position, since neither gravity nor pressure are acting on head 263 or latch 256 in this position.

The foregoing eonstructionpermits the tool to be run in the hole in retracted position with the weight of head 233, guide `231 and bit 232 maintaining the latch in locked position, as shown in Fig. 19. During conventional drilling, the uidlpressure against head 263 maintains latch 256 in locked position, as shown in solid lines in Fig. 20. When it isdesired to commence slant drilling, rotation of bit 222 is stopped and iluid pressure released while bit` 222 is still onlthe bottom of hole 221. Thereupon spring 262raises head 263 unlocking latch 256in the position shown in dotted lines in Fig. 20. The barrel is then `the weight of head 233, guide 231 and bit 232 causingthemselves to slide through barrel 224 intothe extended position as shown in Fig. 19.

In the modification of the invention shown in Fig. l0, the guide 121 comprises a stem 122 having a bit 123 on its lower end and an enlargement 124 intermediate the ends which cooperates with a seat 126 in the `core bit circulation. Excessive pressure or volume of huid causes 1 projection of the stem. This same` relationship exists for Figs. l19 and 20. t

As shownlin Fig. 18, guide 231 may be `relieved in a neck 241 so that the diameter of rod` 231 is` reduced.`

positioml As shown in Figs. i9, `20 and 1l, barrel `224 t is formed with a reduced diametershoulder 251 which forms a limit` for `the upward movement of head 233. Spaoed downwardly from the shoulder inthe` interior wall of :barrel `224 is latch cavity 252, the upper wall 253 of latch cavity being downwardly, outwardly diverging and the lower wall 254 of cavity 2521 likewise beingdownwardl outwardly `diverging.l `Latch 256 carried by head 233 lits into latch'cavity `252, and as shown in Fig. 19, when `in latched position limits downward movement of vhead 233 relative to barrel 224.

127 to act as a tulcrum to dellect the guide. Above ball 124 `is a knuckle joint 128 to which the upper or piston part 129 of the guide is attached. Piston 129 tapers inwardly from top to bottom. Knuckle joint 128 `is provided with a shoe 131 attached zto piston 129 carrying helical coil spring 132, the outer end of which carries a second shoe 133 on the inner wallof the barrel 134. The pressure of spring 132 against knuckle joint 128 biases guide to dellected position. Accordingly, as guide 121 is lowered inside the barrel, it is deflected the maximum deflection being as indicated in Fig. l0. Upper and lower latches 136 and 137, respectively, serve to latch the guide in` retracted and projected positions as in the precedingmodications. As a further modication thespringmay be secured to the barrel rather than to the In the modillcation shown `in Fig. 9, ailexible stem 171 is provided. For this purpose the middle portion of the stem is made in two sections, 172 and 173, with a knuckle joint 174 between the two sections. Knuckle joint 174 is spring-loaded by means of helical spring 176 to require the lower section 173 of the stem to assume an angle relative to upper section 172, which angle determines the degree of dedection `of the hole. However, the force of springl176 in the knuckle joint is such that when the tool is retracted, the upper and lowersu:- tions 172 and 173 assume a lesser angle which facilitates retraction of the guide within the barrel.'

The modification of Fig. 12 is employed to straighten a hole into vertical alignment when it has diverged from vertical direction. Accordingly, the stem `161 of guide gasa-isa 162 isrformedl in` two sectionsf 161a'fand'f161b; withfa knuckle joint1163'b`etween-the'two sections.: When inY projectedl position the v lower r section 16119 by` reason ofL the attraction of gravity, assumes a vertical direction. The referenceY numerals ofother partscorrespond with those in Fig; l.

Although the foregoing'inventionhas been described in some detail by way of illustrationsand example for purposes of clarity of understanding, it is understood that certain changes andmodiications may be practiced within the spirit of' the invention. and scope of. the appended claims.

l claim:V

l.' In combination, a barrel, a'centrallyfapertured .bit onthe lower end of said barrel, a guide extensible and retractable in said barrelthrough the central aperture of said bit, a guide bit on the lowerfend offsaid guide, latching andunlatching meansoperable to latch said guide alternately and repeatedly in extended and in retracted positions and to unlatch said'guide, andmeans operable from a position remote fromfsaidbarrel for/actuating :said

latching and unlatching means, said lastmentionedmeans.

including a drill stem.

2. Thecombination according to claim lwherein said unlatching means comprises upperlatch means located in said barrel and guide to hold said guide in retracted position withsaid centrally aperturedbit andguide. bit in; juxtaposition for drilling and in-which said latching meansfurther comprises lower. latch` means locatedl in said barrel and, guide to hold. said guide in extended position said zcentrally aperturedr-bit for drilling around said guide as a center while said guide remains substantially stationary in a vertical sense.

3. The combination according to claim 2 wherein said latching means are located in said barrel so that said centrally apertured bit drills down over said guide until said centrally apertured bit is in juxtaposition with said guide bit and said latching means latches said guide in retracted position.

4. In combination, a core bit having a substantially central aperture, a barrel above said bit, said barrel being formed with a bore diverging outwardly toward the side Wall of said barrel adjacent the lower end thereof, and a guide within said barrel having a stem dimensioned to project outwardly through said aperture in said bit, said stem slidable within said bore in said barrel and tiltable about said aperture as a fulcrum as the inner end of said stern diverges outwardly in said barrel, a guide bit on the lower end of said stem, and cooperating means on said guide and said barrel to latch said guide with said guide bit substantially retracted within said rst mentioned bit, said cooperating means being repeatedly movable between latched and unlatched positions.

5. The combination of claim 4 which further comprises second cooperating means on said guide and said barrel to latch said guide bit with said guide bit extended remote from said barrel and with said guide bit offset laterally relative to the longitudinal central axis of said barrel.

6. The combination of claim 4 in which said barrel is formed with an internal abutment adjacent the lower end of said bore adapted to engage said guide to limit outward movement of said guide.

7. In combination, a core bit having a substantially central aperture, a barrel above said bit adjacent the lower end of said aperture, said barrel being formed with a bore diverging outwardly toward the side wall of said barrel adjacent the lower end thereof, a guide within said barrel having a guide bit, and a stem dimensioned to project outwardly through said aperture in said bit, said stem being tiltable about said aperture as a fulcrum as the inner end of said stem diverges outwardly in said barrel, cooperating latch means on said barrel and on said guide, said latch means being cooperable to engage in latching relationship when engaged holding said guide inf. elevated-position withinnsaid barrel, and unlatching.l means-operable. to move Isaicl latch means.` to. unlatch.v position responsive to.drillingiuid pressure within .said

barrel above said head.

8. In combination, a core bithavinga substantially central aperture, abarrel above said bit, said barrel being formed with a bore diverging outwardly; toward; the sideV said aperture as a fulcrum, said barrel .being ..formedwith.

a latch hole therein, said head `being hollow, a latch in said'head and projecting outwardly4v to engageisaidflatchhole in said barrelwhensaidlatch is in latched position, means biasing saidflatchztoward'latchedpositiom and means responsive to drilling fluid pressure. within said barrel above said headtoxmove said latchto vunlatched position.

9.- In combination, a bit'having'av substantially central aperture, a barrel. above saidbit, anda guide'withiny said barrel having a stem dimensionedto project outwardly through said centrall aperture, ahead on the upper end of'l said stem slidablewithin saidbarrel, vand a guide bit onfthe lower end of said stem, said'stem being provided with a knuckle joint intermediate its length, resilient'means: biasing the portion of said stern below said knuckle joint.disp`osed` at an angle. relative toL the portionof said stem above: saidknuckle joint, and latching and unlatching means operable to latch said stem alternately and repeatedly in extended and in retracted positions and to unlatch said stem, and means operable from a position remote from said barrel for actuating said latching and unlatching means.

10. The combination according to claim 9 wherein said knuckle joint is located exteriorly of said barrel when said stem is in projected position.

ll. The combination according to claim 9 wherein said knuckle joint is located interiorly of said barrel when said stem is in projected position.

l2. In combination, a barrel, said barrel being provided With a bit at its lower end, said bit having an aperture, a guide extensible and retractible within said barrel having a stern dimensioned to project outwardly through said central aperture, a head on the upper end of said stem slidable within said barrel with a close t, a guide bit on the lower end of said stem, said stem having an upper portion and a lower portion disposed at an angle relative to said upper portion, said barrel and head being provided with cooperating means to locate the portion of said stem below the angle positively disposed relative to said barrel when said guide is projected, and laching and unlatching means operable to latch said stem alternately and repeatedly in extended and in retracted positions and to unlatch said stern, and means operable from a position remote from said barrel for actuating said latching and unlatching means.

13. In combination, a barrel, a bit on the lower end of said barrel having a substantially central aperture, a guide disposed partially within said barrel and extensible through said central aperture in said bit, said guide being dimensioned to project outwardly through said central aperture, and a guide bit on the lower end of said guide, said guide and said barrel having cooperating means whereby, upon extension of said guide, said guide bit is disposed offset relative to the central axis of said barrel, said guide being dimensioned to permit retraction of said guide bit substantially completely within said barrel, said guide being of slightly lesser size than the inside of said barrel and slidable within said barrel for repeated projections and retractions of said guide bit without withdrawal of said barrel, bit or guide from the hole being barrel uid drst cooperative latching means, n

saidlast-snentionedmeans including a drill stem. n

`ISfTOrdIreetimlll comprising a drill bit, said drill bit being formed with a central bore, a hollow barrel seemed abovesaid drillbit, a guide movablewithin said extendablelthrough saidborefmeans to restrain `connllete withdrawal of said guidetrorn` said barrel, slidguide comprising a stem, anda guide bit on thelowerendof said stem, said stem having an upper por.`

tion and a lower potion disposed atan angle relative to said npperportionwhereby, upon proeetionof `said guide, aaidgnide bit extends at ananglerelative to the directiono! said drill bit, said guide tting againstthe inner wall lof `said barrel, `wher'ebyupon application of luid preesnnefromthetop of'sald barrel, said guide is projected, rst cooperative latching means on said guide and barrel movable repeatedly between latched and un-` latched positions, said first cooperative latching means when in latched position holding said guide retracted in "1 saidnaeoondcooperative llatchng` 12 saidbarrehandseeoodeooperativelatchingrneanson said guide and `barrel movable repeatedly between latched and unlatched possitions, said second cooperative latching means wheninklatchedzposition `holding said guide in projected position, said guideubeing retained in either projected or retracted position against unintentional dislodgment from projected or retracted position.

16. The combination of claim14 in which said last named means is responsive to fluid pressure in said barrel.

17.: The combination of claim14 in which said last named means is responsive to mechanical movement of said barrel. n i

18. A device according to claim 15 in which said means to restrain complete withdrawalcomprisesa shoulder [formedin said bit and an enlarged portion adjacent `the upper end of said shank of saidguide. i

19. A device accordingto claim l5 in which the upper end of said bore is counterbored to provide a shoulder in said bitand in which said means to restrain completi.:` withdrawal comprises an enlargement on said stem dimensioned to lit within the counterbored portion of said bore and seat on said shoulder.`

Mmcmainmsslwfmispatem UNITED srATas PATENTS 2,061,317 Breek Nov. l1, 1936 2,142,858 McMahan Jan. 3. 1939 2,227,233 Scott et al. Dec. 31, 1940 2,241,746 Scottet al. May 13, 1941 2,538,545 Whitehead et al.; Ian. 16, 1951 

